1. Technical Field of the Invention
The present invention pertains in general to routing of voice and data traffic in a mobile radio network and, more particularly, to a method and apparatus for routing voice telephone calls received by a mobile radio network to a destination mobile station via an Internet Protocol communication network on a data packet channel.
2. Description of the Related Art
In addition to voice communication, mobile radio networks are increasingly supporting packet data services. Frequently, packet data services are used to connect digital terminal equipment, such as a personal computer communicating through a mobile station operating in the mobile radio network, to an Internet Protocol (IP) communication network such as, for example, an Internet or an Intranet. While voice communication is typically carried across the mobile radio network using circuit-switched communications on a traffic channel, data packets associated with the packet data service are carried across the mobile radio network using packet-switched communications on a packet channel. For example, data packets can be carried on the packet channel using a Transmission Control Protocol/Internet Protocol (TCP/IP).
In certain situations, a mobile station is unable to support a voice connection using circuit-switched communications on the traffic channel. For example, the mobile station may be equipped to operate only in a packet mode using packet-switched communications on the packet channel, with no capability to communicate in a voice mode using circuit-switched communications on the traffic channel. In another example, the mobile station may be operating in the packet mode with the digital terminal equipment connected to the Internet/Intranet on the packet channel at the time when a voice connection to the mobile station is being attempted. In this situation, unless the mobile station is equipped to operate simultaneously in both the packet mode and voice mode, the mobile station needs to release the connection on the packet channel and register on the traffic channel in order to communicate in the voice mode. In yet another example, all traffic channels available for voice communication with the mobile station may be in use and are, therefore, unavailable. In these and other similar situations, the mobile radio network is unable to provide voice communication with the mobile station.
It would be advantageous, therefore, to devise a method and apparatus for providing voice communication between a mobile station operating in a packet mode and a mobile radio network on a communication path other than a voice traffic channel. It would also be advantageous if such a method and apparatus routed the voice communication on a communication network other than the mobile radio network.